With the advent of the Third Generation (3G) era, for operators, the traditional voice service is being replaced by high speed multimedia service, so operators provide users with portable high-speed mobile terminals accessing the network together with a variety of multimedia services, which is an inevitable trend and a new profit growth point. In recent years, various mobile broadband terminal products grow vigorously and change with each passing day, and the technology is also continually updated. Especially for data cards, not only the demands are enormous, but also the requirements for the appearance and function are becoming increasingly higher. A variety of data cards are derived according to the demands of operators and customers from the simple Universal Serial Bus (USB) data card to the multimode & multisystem data card, built-in module and encryption data card.
Now, the design solutions of the mainstream data card are realized by simply combining a USB interface with a 3 G communication module. The existing data cards have the disadvantages below:                1. it can not enable multiple terminals to access the Internet simultaneously: a common data card only enables one user to access the Internet via the 3G network. While using the Wideband Code Division Multiple Access (WCDMA) network, the downlink rate can be up to 7.2 Mbit/s while the uplink rate can be up to 5.76 Mbit/s, which can absolutely support multiple users to access simultaneously. It makes full use of broadband resources for operators and saves a large amount of using expenses for users.        2. it relies on external equipment for power supply: the emphasis of the 3G era is mobility and sharing. But for the traditional USB data card, it has to rely on an equipment with a USB interface for power supply, such as a notebook, to realize the mobility. Inevitably, the allocation of the limited battery resources to data cards will shorten the outdoor usage time of the notebook, thus reducing the mobility remarkably.        3. it is not capable of making effective use of wired broadband: some locations using 3G signals to access the network sometimes also have wired broadband, for example at home or in work place. However, 3G signals sometimes are affected by many factors, such as weather, interference sources around, or use in the place where signal propagation is poor. In the circumstances that 3G signal propagation is poor and there is wired broadband available, the existing data card is not capable of making use of wired broadband.        
A Chinese utility model whose application number is 200920057829.X discloses a wireless router which includes: a wireless broadband Wireless Fidelity (Wi-Fi) router, a 3G wireless communication module, a single-chip microcomputer AT89C52 and power supply unit. The utility model accesses the Internet via 3G signals and supports multiple terminals to access the Internet simultaneously via Wi-Fi routers, overcoming the disadvantages that 3G network cards only support one single user to access the Internet and Wi-Fi routers are not capable of accessing the mobile network. However, firstly the utility model does not access wired Asymmetrical Digital Subscriber Line (ADSL) signals, so it cannot make full use of wired broadband if the communication quality of 3G signals is affected by environmental factors. Secondly, the utility model is incapable of functioning without external power supply, so the portability and mobility is significantly degraded. Lastly, the 3G module is not integrated with the CPU in the utility model, which causes too many interface circuits, and the interface circuit does not adopt a high speed Secure Digital Input Output (SDIO) interface, so the speed and stability require improvement.